The Norton lectures at Harvard retain their prestige, even though the annual speakers rarely achieve the general interest of such past invitees as Igor Stravinsky and Leonard Bernstein. Ten years ago the venerable Ashbery (Your Name Here; Forecasts, July 24) returned to his undergraduate alma mater to give the customary six lectures, here retouched and presented with documentation. They deal with ""certifiably minor"" writers whom Ashbery, as a self-confessed nonscholar, feels more at ease in discussing: John Clare, Thomas Lovell Beddoes, Raymond Roussel, John Wheelwright, Laura Riding, and David Schubert. He relies heavily on the lives of the arid Boston Brahmin poet Wheelright and depression-era American Schubert for entree into their work, and, in the case of all the writers, liberally invokes secondary sources. The lectures themselves are unlikely to raise strong objections or reapprisals, as the Schubert particularly seems designed to do, but Ashbery's fans will appreciate a look into his reading. Borges's lectures from 1967-68, posthumously transcribed, retread familiar critical territory for the poet and maker of masterly Ficciones. Although titles like ""The Riddle of Poetry,"" ""The Telling of the Tale,"" and ""Thought and Poetry,"" hold abstract promise, these are the sort of musings on literature that Borges carefully kept out of his diamondlike stories but allowed into much of his critical prose: wistful, retro, and slightly befuddled, such as when Borges cites The Arabian Nights in the middle of a paragraph about Jewish mysticism or calls Oscar Wilde ""a writer for boys."" The stilted afterword by Mihailescu, a professor of modern languages at the University of Western Ontario, doesn't help. The delay in the issuing of these two books already boded poorly; their release now seems perfunctory. (Oct.)